Epithelial tubes constitute many of the major organs in our body. Analysis of tube containing organs in systems such as Drosophila or the mouse have demonstrated that tubulogenesis takes place by carefully regulated changes in cell-shape and organization. Mis-regulation of cell shape change and migration is often a hallmark of human cancers, suggesting that investigating the cellular mechanisms that drive organogenesis in a developing animal may lead to further understanding of oncogenic events. In the proposed study, two tube-containing organs in Drosophila, the trachea and salivary gland, will be analyzed. The first aim is designed to characterize changes in both membrane distribution and cytoskeletal dynamics during tracheal and salivary gland development. Antibody staining and live-imaging fluorescence microscopy will be used. The second aim is designed to determine if the planar cell polarity (PCP) pathway is utilized during tubulogenesis. The role of Fat, a cell adhesion molecule involved in PCP, during tracheal and/or salivary gland development will be characterized. In the third aim, a mutagenesis screen will be performed to identify new molecules that contribute to tube morphology.